New ELISA for walnut allergens

Monday, 20 July 2009 20:47

Researchers from the Food Allergy Research & Resource Program (FARRP), at the University of Nebraska have published the results of their work to develop a rapid, sensitive, and specific enzyme-linked immunosorbent assay (ELISA) method for the detection of walnut protein residues in food.

Several varieties of English walnuts, both raw and roasted, were used to develop the ELISA, and the performance was validated by testing known amounts of walnut (0 to 100 ppm) either spiked into or manufactured into milk chocolate, cookies, muffins, or ice cream. Recoveries of 1 to 100 ppm walnut-in-chocolate ranged from 71.6% to 119%± 7% to 16.5%.

The kit was used to test close to 100 foods for any cross reactions, and while substantial cross-reactivity was seen with pecan, minimal cross-reactivity was found with any of the other foods tested. The authors are confident this ELISA can be used to detect undeclared walnut residues in foods and ingredients and as a tool to validate the effectiveness of allergen control programs for walnuts.

Reference: Journal of Food Science, June 2009 DOI 10.1111/j.1750-3841.2009.01214.x